Specimen Requirements

1. Draw blood in a blue-top (citrate) tube(s). Spin down, remove plasma, spin plasma again, and place 0.5 mL of citrate platelet-poor plasma in plastic vial. (Glass vial is not acceptable.)

Note:  Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.
2. Freeze specimen immediately at ≤-40° C, if possible.
3. Send specimen frozen.
Note:  1. Each coagulation assay requested should have its own vial.
2. Heparin treatment may lower plasma antithrombin.